The second paragraph is literally a threat.

"Palestine must be slaughtered else the jews might want to live where I would want to slaughter them"

Nobody:

German liberals for some fucking reason: "MY GRANDPAPPY WAS A NAZI :DDDDDDDD"

Instead of exterminating those native to Palestine out of fear of antisemitism beyond Isn'trael, why don't you advocate for the world to not be antisemitic instead? It seems like it'll benefit a lot more people than trying to slaughter an entire group of people would.

Sadly the biggest impact of WWII on German culture was that "having learned from the tragedy" became a central part of the German identity, whether any learning actually took place or not, so now they will use their Opa having been a nazi as justification for just about any belief.